ANNULAR BARRIER AND WELL SYSTEM FOR LOW PRESSURE ZONE Russian patent published in 2020 - IPC E21B33/12 E21B34/10 

FIELD: drilling of wells.

SUBSTANCE: group of inventions relates to well annular barrier, well completion system and method of drilling beyond low pressure zone in formation. Annular barrier comprises: tubular part for installation in form of part of tubular structure of well, wherein tubular part comprises hole and inner part, having internal pressure; an expanding metal coupling surrounding the tubular part and having an inner surface facing the tubular portion, and an outer surface facing the wellbore wall; wherein each end of expanding metal coupling is connected to tubular part; annular space between inner surface of expanding metal coupling and tubular part, wherein annular space has space pressure; and a valve system comprising a first valve and a second valve. Second valve is configured to pass fluid medium under pressure inside annular space for expanding of expanding metal coupling and with the possibility of preventing fluid flow from the annular space into the inner part of the tubular part. First valve has a first position providing connection with possibility of transfer of fluid medium between inner part of tubular part and second valve for expansion of expansion metal coupling with increase of internal pressure, and second position, providing connection with possibility of fluid medium transfer between annular space and annular space. First valve is configured to shift from first position to second position when space pressure is above internal pressure.

EFFECT: technical result is creation of improved annular barrier for well completion system or drilling system, which allows to continue drilling beyond the above very low pressure zone.

15 cl, 12 dwg